Sulphuric acid pan and peocess of making the same



(No Model.)

R. KUOH. SULPHURIG ACID PAN AND PROCESS OF MAKING THE SAME. No.474,527.- Paten'ted May 10,1892.

IIVVEIVTOH B) W 4 5 1 yaw 5. @{UMM f wziv f ATTORNEYS.

A ENITED STATES PATENT OFFICE.

RICHARD KIICII, OF HANAU-ON-TI'IE-MAIN, GERMANY, ASSIGNOR TOW'ILHELMCARL I-IERAEUS, IVILHELM HERAEUS, AND HEINRICH I-IERAEUS, OF SAME PLACE.

SULPHURlC-ACID PAN AND PROCESS OF MAKING THE SAME.

SPECIFICATION forming part of Letters Patent No. 474,527, dated May 10,1892.

Application filed April 10, 1891- Serial No. 389,230. (No model.)

To to whom it may concern.-

Be it known that I, RICHARD KI'JCH, of Hanau-on-the-Main, Germany, haveinvented an Improvement in Sulphuric-Acid Pans and Process of Making theSame,of which the following is a specificatiomreference being had totheaccompanying drawings, forming part of the same, in which- Figure 1 is aperspective view of a furnace whereby my invention maybeaccomplished;

Fig. 2, a plan view of the same; Fig. 3, a perspective view of theplatinum box ready to receive the gold, and Fig. 4 a cross-sectionthereof. Fig. 5 is a cross-section of the pan.

A represents my improved sulphuric-acid pan, consisting of an outerthickness 19 of platinum and an inner thickness 9 of gold.

B represents a furnace having pillars or supports 0, upon which theplatinum bar or 20 sheet a,having rim 1), rests (see Fig. 2) in theprocess of heating. This furnace is furnished with a door or opening 61in the lower portion, and a cap or cover (2, having suitable opening fto regulate the intensity of the heat.

This invention relates to an improvement in pans for concentratingsulphuric acid. Heretofore the better class of pans for concentratingsulphuric acid have been made of platinum, which is a substance superiorto glass or porcelain pans, for the reason that it permits the contentsto be exposed to a higher degree of heat; but, nevertheless, pans madeof platinum are liable to be consumed by the sulphuric acid-that is tosay, although sul- 3 5 phuric acid up to 93 Baum does not affectplatinum to any noticeable extent it does, when concentrated to a higherdegreesay 97-eat into the metal to quite a considerable extent.

Now the object of my invention is to so construct these platinum pansthat they will resist the corrosive action of the highly-concentratedsulphuric acid, and will therefore be more durable than those made ofplatinum alone. I have found that gold is a substance which will not benoticeably affected byhighly-concentrated sulphuric acid; but theexpense of gold is so great that it alone cannot properly be used forthe purpose; but an inner lining of gold, if properly connected with themain body of platinum, will produce the desired result. In myexperiments I have found that it would be impracticable to produce aninner lining of gold on platinum by any of the plating processes now inuse, for the reason that the least defect in the thin covering of thegold rendered the entire pan practically one of platinum alone, exposingsufficient of the platinum to enable the sulphuric acid to reach thewhole.

My invention consists, mainly, in applying a lining g of cast gold tothe platinum body 19 of a. sulphuric-acid pan by first heating aplatinum bar or sheet ain the furnace B illustrated'in the drawings, orin any suitable furnace, to a degree higher than the meltingpoint of thegold, and then casting melted gold upon the top of this heated platinumbar or plate. By this means I obtain a complete and perfect connectionof the two metals upon chilling, as the cast-gold unites with theplatinum and forms an intermediate layer of alloy of gold and platinum.This absolute connection of the two metals is not merely a superpositionof the one upon the other, such as would be obtained by ordinary platingor pressure, and I am enabled to render the gold lining as thick asdesired and to like wise make it a complete lining, for should in theprocess specified a portion of the platinum not be covered with the goldI will have no difficulty upon re-heating the platinum to cover thenaked spot with the necessary quantity of gold. The platinum plate a hasa rim 1), which prevents the liquid from escaping. The platinum plate orbar a thus covered with gold is then disconnected from the rim 1) andthereupon rolled out to reduce its thickness, leaving the gold coveringin the proportionate thickness always in position. Hence I can producemy pan A from a chunk or ingot a of platinum to which the gold coveringhas been applied in manner specified, said chunk or ingot being thenrolled out into plates of desired thickness, producing them with therequisite gold covering. The pan A itself of this construction ispractically indestructible and,because of its resistance to thesulphuric acid, much more economical in use, though higher in the firstcost than a pan made entirely .of platinu in, as heretofore.

I am aware of patent to Kearsing, No. 111,551, dated February 7, 1871,in Which is described a foil for filling teeth, consisting of gold andplatinum fused and rolled together into a compound sheet, and I herebydisclaim what is disclosed in said patent, the present inventionconsisting of a sulphuric-acid pan composed of layers of platinum andgold joined by a substantial intermediate layer of alloy of platinum andgold and a novel process of manufacturing the same.

What I claim, and desire to secure by Letters Patent, is

1. The herein-described process of uniting RICHARD KtioH.

Witnesses:

ALvEsro S. HOGUE, JEAN GRUND.

